GridView Checkbox bringing back all checkbox even if only one is selected

#region GetJobs
   protected void GetJobs()
   {
      try
      {
         int index = 0;
         CheckBox cb = new CheckBox();
         Session["ReportConnectionString"] = ",";

         while (index < GridViewSearch.Rows.Count)
         {
            GridViewRow checkedRow = GridViewSearch.Rows[index];
            cb = (CheckBox)checkedRow.FindControl("CheckBoxEdit");

            if (cb.Checked == true)
               Session["ReportConnectionString"] = Session["ReportConnectionString"].ToString() + GridViewSearch.DataKeys[index].Values["AreaId"].ToString() + ",";

            index++;
         }
      }
      catch (Exception ex)
      {
         
      }
   }
#endregion "GetJobs"

#region ButtonSelect_Click
   protected void ButtonSelect_Click(object sender, EventArgs e)
   {
      try
      {
         CheckBox cb = new CheckBox();

         foreach (GridViewRow row in GridViewSearch.Rows)
         {
            cb = (CheckBox)row.FindControl("CheckBoxEdit");
            if (!cb.Checked)
               cb.Checked = true;
            else
               cb.Checked = false;
         }
      }
      catch (Exception ex)
      {

      }
   }
#endregion ButtonSelect_Click

protected void ButtonPrint_Click(object sender, EventArgs e)
{
   try
   {
      GetJobs();
      Session["FromURL"] = "~/Reports/SpaceUtilised.aspx";

      Session["ReportName"] = "Space Utilised";

      Microsoft.Reporting.WebForms.ReportParameter[] RptParameters = new Microsoft.Reporting.WebForms.ReportParameter[5];

      // Create the ConnectionString report parameter
      //string areaId = Session["ReportConnectionString"].ToString();
      //RptParameters[0] = new Microsoft.Reporting.WebForms.ReportParameter("ConnectionString", areaId);
      string areaId = Session["ReportConnectionString"].ToString();
      RptParameters[0] = new Microsoft.Reporting.WebForms.ReportParameter("ConnectionString", areaId);

      // Create the WarehouseId report parameter
      RptParameters[1] = new Microsoft.Reporting.WebForms.ReportParameter("WarehouseId", Session["WarehouseId"].ToString());

      // Create the AreaId report parameter
      RptParameters[2] = new Microsoft.Reporting.WebForms.ReportParameter("AreaId", Session["AreaId"].ToString());

      RptParameters[3] = new Microsoft.Reporting.WebForms.ReportParameter("ServerName", Session["ServerName"].ToString());

      RptParameters[4] = new Microsoft.Reporting.WebForms.ReportParameter("DatabaseName", Session["DatabaseName"].ToString());

      Session["ReportConnectionString"] = null;

      Session["ReportParameters"] = RptParameters;

      Response.Redirect("~/Reports/Report.aspx");
   }
   catch { }
}

protected void Page_Load(object sender, EventArgs e)
{
   if(!Page.IsPostBack)
      Session["AreaId"] = -1;
}

protected void ButtonPrint_Click(object sender, EventArgs e)
{
   try
   {
      Session["FromURL"] = "~/Reports/SpaceUtilised.aspx";

      Session["ReportName"] = "Space Utilised";

      Microsoft.Reporting.WebForms.ReportParameter[] RptParameters = new Microsoft.Reporting.WebForms.ReportParameter[5];

      // Create the ConnectionString report parameter
      string strReportConnectionString = Session["ReportConnectionString"].ToString();
      RptParameters[0] = new Microsoft.Reporting.WebForms.ReportParameter("ConnectionString", strReportConnectionString);

      // Create the WarehouseId report parameter
      RptParameters[1] = new Microsoft.Reporting.WebForms.ReportParameter("WarehouseId", Session["WarehouseId"].ToString());

      // Create the AreaId report parameter
      RptParameters[2] = new Microsoft.Reporting.WebForms.ReportParameter("AreaId", Session["AreaId"].ToString());

      RptParameters[3] = new Microsoft.Reporting.WebForms.ReportParameter("ServerName", Session["ServerName"].ToString());

      RptParameters[4] = new Microsoft.Reporting.WebForms.ReportParameter("DatabaseName", Session["DatabaseName"].ToString());

      Session["ReportParameters"] = RptParameters;

      Response.Redirect("~/Reports/Report.aspx");
   }
   catch { }
}

protected void CheckBoxAll_OnCheckedChanged(object sender, EventArgs e)
{
   if (CheckBoxAll.Checked)
   {
      Session["AreaId"] = -1;
      AreaSearch1.Visible = false;
   }
   else
      AreaSearch1.Visible = true;
}